In general, for the electric motor car, a configuration for collecting electric power from an overhead wire, a third rail, or the like with a current collector and driving a motor using the collected power is adopted.
In recent years, because the performance of power storage elements such as a secondary battery and an electric double layer capacitor is improved, development of a system is underway in which the power storage elements are mounted on an electric motor car, collected electric power is stored in the power storage elements, and a motor is driven by using both the electric power stored in the power storage elements and electric power collected by a current collector.
As such a system, for example, there is an electric motor car control apparatus disclosed in Patent Document 1 described below. In this electric motor car control apparatus, to control power flow between an overhead wire and a power storage element, a DCDC converter is provided between the current collector and the power storage element.
Although not provided in the electric motor car control apparatus disclosed in Patent Document 1, in the system of this type, a reactor is provided between the DCDC converter and the overhead wire and attenuation of a harmonic current output from the DCDC converter to the overhead wire side is performed by an LC filter circuit including this reactor and an input capacitor.    Patent Document: Japanese Patent Application Laid-open No. 2007-274756